Place butter in a bowl and set aside.
Place marshmallows in a large microwave-safe bowl, and microwave on High for 30 seconds to 1 minute to start melting the marshmallows. Mix the water and vanilla extract into the hot marshmallows, and stir until the mixture is smooth.
Slowly beat in confectioners' sugar, one cup at a time, until you have a sticky dough. Reserve 1 cup of powdered sugar for kneading. The dough will be very stiff.
Rub your hands thoroughly with butter, and begin kneading the dough. As you knead, the dough will become more workable and pliable. Place the dough out onto a work surface dusted with confectioners' sugar. Continue kneading until the fondant is smooth and no longer sticky to the touch, 5 to 10 minutes.
Form the fondant into a ball. Wrap it tightly in plastic wrap and refrigerate overnight.
When ready to use, allow the fondant to come to room temperature, and roll it out on a flat surface dusted with confectioners' sugar.
By Laurel from Port Orchard, WA
There are about a thousand recipes online and the end results are beautiful and delicious! I've made fondant for a fraction of the cost than you can get pre-made at a craft store! And in my opinion, it tastes much better!
By Carrie from El Paso, TX
Some recipes on line call for lemon or orange oil, I used clear vanilla or regular vanilla, or any other flavorings you would like. I have also used invisible Kool-Aid or colored Kool-Aid for flavor. Fun!
By Mary from Atascadero, CA